I got error when trying to set java JVM heap size

Question

I have some code running on AWS device farm, that got java heap out of memory exception. So I tried to run some java JVM heap settings locally to see if that works. Here is what I tried:

set java -Xms262144, I know that is in byte, thus 262144 probably doesn't make sense, as too small, but at least that proves this script is correct in syntax.

C02ZxxxGVCF:util i7xxxx$ java -Xms262144
Error occurred during initialization of VM
 Too small initial heap

So next I did increase the size to 268435456 which is 256Mb, but it doesn't seem to take that at all. Please see below output from terminal.

C02ZxxxGVCF:util i7xxxxx$ java -Xms268435456
Usage: java [options] <mainclass> [args...]
           (to execute a class)
   or  java [options] -jar <jarfile> [args...]
           (to execute a jar file)
   or  java [options] -m <module>[/<mainclass>] [args...]
       java [options] --module <module>[/<mainclass>] [args...]
           (to execute the main class in a module)
   or  java [options] <sourcefile> [args]
           (to execute a single source-file program)

 Arguments following the main class, source file, -jar <jarfile>,
 -m or --module <module>/<mainclass> are passed as the arguments to
 main class.

Any tips please?

Hi thanks but it is an appium test project, where there doesn't seem to have a main class? How do I specify that paramter? — Huibin Zhang, Mar 04 '21 at 15:25
Even so, 262k bytes is still far too small of a default heap size. It should be at least about 1 MB (I think), but don't [optimize prematurely](https://stackoverflow.com/q/385506). Instead, just let the JVM help itself. — Julia, Mar 04 '21 at 15:28
@Julia yes I know, that just to prove the syntax is correct, but when I put is as "java -Xms256m" or "java -Xms1g" or "java -Xms256M" it doesn't work. — Huibin Zhang, Mar 04 '21 at 15:49
Try to set both – stack and heap size on really big sizes: -Xms500m -Xss500m — Kaplan, Mar 04 '21 at 17:12
first line of usage: `java [options] ` after options there must be the name of main class: e. g. `java -Xms256M Test` (or add `-version`) — , Mar 04 '21 at 17:18
to set it as default, try setting environment variables like `JAVA_TOOL_OPTIONS` — , Mar 04 '21 at 17:24

score 0 · Answer 1 · answered May 10 '21 at 14:33

As shown in the "Usage", you must specify the Java class name or the jar name. For example,

java -Xms256m HelloWorld

Here instead of HelloWorld specify your java class name or

java -Xms256m -jar hello.jar

Here instead of HelloWorld specify your jar name

I got error when trying to set java JVM heap size

1 Answers1